Move to gawk-3.1.7.

1 files changed, 38 insertions, 0 deletions

diff --git a/libsigsegv/src/leave-setcontext.c b/libsigsegv/src/leave-setcontext.c
new file mode 100644
index 00000000..e383cf96
--- /dev/null
+++ b/libsigsegv/src/leave-setcontext.c
@@ -0,0 +1,38 @@
+/* Leaving a signal handler executing on the alternate stack.
+   Copyright (C) 2002  Bruno Haible <bruno@clisp.org>
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software Foundation,
+   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+
+#include <signal.h>
+#include <ucontext.h>
+
+void
+sigsegv_reset_onstack_flag (void)
+{
+  ucontext_t uc;
+
+  if (getcontext (&uc) >= 0)
+    /* getcontext returns twice.  We are interested in the returned context
+       only the first time, i.e. when the SS_ONSTACK bit is set.  */
+    if (uc.uc_stack.ss_flags & SS_ONSTACK)
+      {
+        uc.uc_stack.ss_flags &= ~SS_ONSTACK;
+        /* Note that setcontext() does not refill uc.  Therefore if
+           setcontext() keeps SS_ONSTACK set in the kernel, either
+           setcontext() will return -1 or getcontext() will return a
+           second time, with the SS_ONSTACK bit being cleared.  */
+        setcontext (&uc);
+      }
+}